1. Field of the Invention
The present invention relates to a position detecting apparatus for a moving object. More particularly, the present invention relates to a position detecting apparatus, which may be used irrespective of motor rotation direction.
2. Related Art
Various position detectors for a moving body such as a vehicle power window device are proposed in JP-A-8-29114 and JP-A-9-236431.
In the proposed position detector, a moving contact plate and a pulse plate are accommodated in a cover plate to be driven by a motor output shaft. A plurality of fixed sliding contacts are directly fixed to the cover plate. The moving contact plate is provided with a moving contact for a detection of a specified rotational position of the motor output shaft, while the pulse plate is provided with a sequential pulse pattern for a detection of each rotational movement of the motor output shaft. Thus, the sliding contacts slide on the moving contact plate and the pulse plate to generate pulse signals indicative of rotational positions of the motor output shaft, when the moving contact plate and the pulse plate rotate with the rotation of the motor.
In the vehicle power window device, there are cases where a forward direction rotation of the motor output shaft is used to raise a door window glass and where a reverse direction rotation of the motor output shaft is used to raise the window glass. Further, the position detector used in the vehicle power window device is attached to the motor output shaft in opposite directions depending on the cases where the power window device is for the vehicle left side door or the vehicle right side door. Thus, as the moving contact plate rotates in different directions depending on the motor rotation direction and the side of the door, the position detector must be designed separately even for the same vehicle depending on the motor rotation direction and the side of the door.